Steel houses are generally defined as steel panel construction buildings comprising light gage frame members made from sheet steels not less than 0.4 mm and less than 2.3 mm in thickness and structural face members combined with said frame members. When building relatively low buildings, such as of two or three stories, with such steel members, building has conventionally been carried out by the platform construction method (the so-called frame-wall construction method) that completes one story after another by first completing the ground story by laying the floor thereof and placing the wall panels for one story and then mounting the floor panel of the upper story on the wall panels of the ground story, thus completing one story after another. This platform construction method has an advantage of eliminating the need for heavy machines and scaffolds.
On the other hand, the platform construction method joins the wall panels of the upper and lower stories by using hold-down hardware (sometimes referred to as HD hardware) and long bolts and provides metal reinforcements to transfer the compressive force working on the floor panel joists whose ends are inserted between the wall panels of the upper and lower stories. The need to provide such hold-down hardware and metal reinforcements complicates the structure of buildings.
The design method for steel houses built by the platform construction method is explained by reference to schematic drawings in FIG. 10.
As shown in FIG. 10, the platform construction method first completes the floor of the ground story (not shown) and builds the walls 2 of the ground story by mounting the wall panels 1 for one story thereon. After the completion of the walls 2 of the ground story, the floor panel 3 for the upper story is mounted and, then, the walls 4 of the second story are constructed by mounting the wall panels 1 for one story on said floor panel 3. The wall panel 1 comprises a rectangular wall frame consisting of vertical frame members and top and bottom horizontal frame members and a structural face plate attached thereto. The floor panel 3 consists of a floor plate attached to side and end joists.
In a steel house built, as described above, by the platform construction method, the walls 2 and 4 of the upper and lower stories are joined together by hold-down hardware 5 and other connection hardware by way of the floor 3a. Japanese Unexamined Patent Publication No. 10-311110 discloses an example of the joined construction described above, as shown in FIG. 11.
In FIG. 11, a wall panel 1 for the upper and lower stories comprises a wall frame consisting of vertical frame members 10 and a top and a bottom horizontal frame members 11 and 12, all made of light-gage channels of sheet steels, and a structural face plate 13 (hereinafter referred to as the face plate) attached to said frame members. In the upper part of the wall panel 1, as shown in FIG. 11, the vertical frame members 10 and top horizontal frame member 11 are fastened together by the hold-down hardware 5. In the lower part of the wall panel 1, as shown in FIG. 11, the vertical frame members 10 and bottom horizontal frame member 12 are fastened together by the hold-down hardware 5.
The floor panel 3 comprising a floor plate 17 mounted on side and end joists of light-gage channels of sheet steels is disposed between the upper end of the wall panel 1 of the lower story and the lower end of the wall panel 1 of the upper story as a partition therebetween. Connection hardware 8 is attached to the floor panel 3. The connection hardware 8 comprises a cylindrical bolt holder 6 and horizontal flanges 7 fastened at the top and bottom ends thereof, said top and bottom flanges 7 having a bolt insertion hole 7a. The upper and lower wall panels 1 are joined together by connecting a bolt 14 passed through the bolt holder 6 of the connection hardware to the hold-down hardware 5 attached to the wall panels 1 of the upper and lower stories. The connection hardware 8 is vertically mounted so as to contact the top and bottom ends of the joists 15 and 16, whereas the bolt 14 is passed along the hold-down hardware 5 of the lower story and through the bolt holder 6 of the connection hardware 8 and the floor plate 17 and the bottom frame member 12 of the wall frame of the upper story, and then fastened by a nut 18 to the hold-down hardware 5 of the upper story. The lower end of the bolt 14 is similarly fastened by a nut 18 to the hold-down hardware 5 of the lower story. Thus, the hold-down hardware 5 joins the wall panels 1 of the upper and lower stories by way of the floor panel 3.
The platform construction method just described requires intricate design that, in turn, makes field work difficult because connection of the wall panel 1 to the floor panel 3 and that of the wall panels 1 of the upper and lower stories require hold-down hardware 5, connection hardware 8 and other metal reinforcements. If such metal reinforcements are eliminated or reduced in order to avoid an increase in the number of structural members and complicated design, construction becomes hazardous. Furthermore, the conventional platform construction method tends to require intricate design because load transfer paths are complicated.
Japanese Unexamined Patent Publication No. 11-140975 discloses a method for improving the platform construction method requiring hold-down hardware. This improving method provides multiple vertical frame studs constituting a wall surface frame that are expanded throughout the whole stories and hold a floor panel and a wall panel surface member fastened thereto, laterally and vertically.
However, the technology disclosed in Japanese Unexamined Patent Publication No. 11-140975 defies a simple method practicable with the platform construction method in which unitized wall panels, which are prepared by fastening a structural surface member to a rectangular wall frame, are joined together, one story after another. The technology disclosed in Japanese Unexamined Patent Publication No. 11-140975 involves a problem that the time and the trouble in field work increase because wall panel surface members must be attached at the construction site after all vertical frame studs extending to the uppermost story have been joined together.